The Hot Shoe Adapter 3/8" to 1/4" is part of the CoolArm11, and may be used to mount an accessory with 1/4" socket to the hot shoe of a camera.
 
The thread is  3/8" to 1/4": the thread top part is 1/4" , bottom part is 3/8".
 
Includes:
2x Shoe Mount Adapter
 
Material: Aluminum Alloy
 
Net Weight: 60g